I removed the graph name projection from the OPTIONAL:
PREFIX schema: <https://schema.org/>
PREFIX foaf: <http://xmlns.com/foaf/0.1/>
PREFIX sioc: <http://rdfs.org/sioc/ns#>
SELECT DISTINCT ?employee ?reportsToEmployee ?reportsToEmployeeLabel
WHERE
{ GRAPH ?docGraph
{ ?doc sioc:has_container <https://localhost:4443/employees/> ;
foaf:primaryTopic ?employee
OPTIONAL
{ ?employee schema:sponsor ?reportsToEmployee }
}
OPTIONAL
{ { SELECT ?reportsToEmployee ?reportsToEmployeeLabel
WHERE
{ { ?reportsToEmployee <http://purl.org/dc/terms/title>
?reportsToEmployeeLabel }
UNION
{ GRAPH ?reportsToEmployeeLabelGraph
{ ?reportsToEmployee
<http://purl.org/dc/terms/title> ?reportsToEmployeeLabel }
}
}
}
}
}
ORDER BY ?doc
RDF4J now produces 9 results (same as Dydra), but Fuseki returns 2417 rows.
On Tue, Nov 24, 2020 at 3:33 PM Martynas Jusevičius
<[email protected]> wrote:
>
> Yes, it looks like this is due to the different treatment of the named graphs.
>
> PREFIX schema: <https://schema.org/>
> PREFIX foaf: <http://xmlns.com/foaf/0.1/>
> PREFIX sioc: <http://rdfs.org/sioc/ns#>
>
> SELECT (COUNT(?docGraph) AS ?docGraphCount) WHERE {
> GRAPH ?docGraph {
> ?doc sioc:has_container <https://localhost:4443/employees/>;
> foaf:primaryTopic ?employee.
> OPTIONAL { ?employee schema:sponsor ?reportsToEmployee. }
> }
> }
>
> Dydra: ?docGraphCount = 9
> Fuseki: ?docGraphCount = 9
> RDF4J: ?docGraphCount = 9
>
>
> PREFIX schema: <https://schema.org/>
> PREFIX foaf: <http://xmlns.com/foaf/0.1/>
> PREFIX sioc: <http://rdfs.org/sioc/ns#>
>
> SELECT (COUNT(?reportsToEmployeeLabelGraph) AS
> ?reportsToEmployeeLabelGraphCount) WHERE {
> GRAPH ?reportsToEmployeeLabelGraph { ?reportsToEmployee
> <http://purl.org/dc/terms/title> ?reportsToEmployeeLabel. }
> }
>
> Dydra: ?reportsToEmployeeLabelGraphCount = 2409
> Fuseki: ?reportsToEmployeeLabelGraphCount = 2409
> RDF4J: ?reportsToEmployeeLabelGraphCount = 2409
>
> On Tue, Nov 24, 2020 at 3:14 PM Lorenz Buehmann
> <[email protected]> wrote:
> >
> > It looks more like the cartesian happens on the graphs - how many graph
> > do you have matching the first and the second part?
> >
> > On 24.11.20 14:27, Martynas Jusevičius wrote:
> > > Hi,
> > >
> > > despite using SPARQL for years, cases where different implementations
> > > return different results leave me scratching my head. Can someone help
> > > me out with this?
> > >
> > > I have a rather simple query:
> > >
> > > PREFIX schema: <https://schema.org/>
> > > PREFIX foaf: <http://xmlns.com/foaf/0.1/>
> > > PREFIX sioc: <http://rdfs.org/sioc/ns#>
> > >
> > > SELECT * WHERE {
> > > GRAPH ?docGraph {
> > > ?doc sioc:has_container <https://localhost:4443/employees/>;
> > > foaf:primaryTopic ?employee.
> > > OPTIONAL { ?employee schema:sponsor ?reportsToEmployee. }
> > > }
> > > }
> > > ORDER BY ?doc
> > >
> > > Dydra returns 9 results:
> > >
> > > employee,reportsToEmployee
> > > https://localhost:4443/employees/1/#this,https://localhost:4443/employees/2/#this
> > > https://localhost:4443/employees/2/#this,
> > > https://localhost:4443/employees/3/#this,https://localhost:4443/employees/2/#this
> > > https://localhost:4443/employees/4/#this,https://localhost:4443/employees/2/#this
> > > https://localhost:4443/employees/5/#this,https://localhost:4443/employees/2/#this
> > > https://localhost:4443/employees/6/#this,https://localhost:4443/employees/5/#this
> > > https://localhost:4443/employees/7/#this,https://localhost:4443/employees/5/#this
> > > https://localhost:4443/employees/8/#this,https://localhost:4443/employees/2/#this
> > > https://localhost:4443/employees/9/#this,https://localhost:4443/employees/5/#this
> > >
> > > Fuseki 3.16.0 returns 9 results:
> > >
> > > employee,reportsToEmployee
> > > https://localhost:4443/employees/1/#this,https://localhost:4443/employees/2/#this
> > > https://localhost:4443/employees/2/#this,
> > > https://localhost:4443/employees/3/#this,https://localhost:4443/employees/2/#this
> > > https://localhost:4443/employees/4/#this,https://localhost:4443/employees/2/#this
> > > https://localhost:4443/employees/5/#this,https://localhost:4443/employees/2/#this
> > > https://localhost:4443/employees/6/#this,https://localhost:4443/employees/5/#this
> > > https://localhost:4443/employees/7/#this,https://localhost:4443/employees/5/#this
> > > https://localhost:4443/employees/8/#this,https://localhost:4443/employees/2/#this
> > > https://localhost:4443/employees/9/#this,https://localhost:4443/employees/5/#this
> > >
> > > So far so good -- the results are identical. Now I append an OPTIONAL
> > > to the end of the query:
> > >
> > > PREFIX schema: <https://schema.org/>
> > > PREFIX foaf: <http://xmlns.com/foaf/0.1/>
> > > PREFIX sioc: <http://rdfs.org/sioc/ns#>
> > >
> > > SELECT ?employee ?reportsToEmployee ?reportsToEmployeeLabel WHERE {
> > > GRAPH ?docGraph {
> > > ?doc sioc:has_container <https://localhost:4443/employees/>;
> > > foaf:primaryTopic ?employee.
> > > OPTIONAL { ?employee schema:sponsor ?reportsToEmployee. }
> > > }
> > > OPTIONAL {
> > > GRAPH ?reportsToEmployeeLabelGraph { ?reportsToEmployee
> > > <http://purl.org/dc/terms/title> ?reportsToEmployeeLabel. }
> > > }
> > > }
> > > ORDER BY ?doc
> > >
> > > Dydra returns 9 results:
> > >
> > > employee,reportsToEmployee,reportsToEmployeeLabel
> > > https://localhost:4443/employees/1/#this,https://localhost:4443/employees/2/#this,Fuller
> > > https://localhost:4443/employees/2/#this,,
> > > https://localhost:4443/employees/3/#this,https://localhost:4443/employees/2/#this,Fuller
> > > https://localhost:4443/employees/4/#this,https://localhost:4443/employees/2/#this,Fuller
> > > https://localhost:4443/employees/5/#this,https://localhost:4443/employees/2/#this,Fuller
> > > https://localhost:4443/employees/6/#this,https://localhost:4443/employees/5/#this,Buchanan
> > > https://localhost:4443/employees/7/#this,https://localhost:4443/employees/5/#this,Buchanan
> > > https://localhost:4443/employees/8/#this,https://localhost:4443/employees/2/#this,Fuller
> > > https://localhost:4443/employees/9/#this,https://localhost:4443/employees/5/#this,Buchanan
> > >
> > > Fuseki 3.16.0 returns 2400+ results:
> > >
> > > employee,reportsToEmployee,reportsToEmployeeLabel
> > > https://localhost:4443/employees/1/#this,https://localhost:4443/employees/2/#this,Fuller
> > > https://localhost:4443/employees/2/#this,https://localhost:4443/,Root
> > > https://localhost:4443/employees/2/#this,https://localhost:4443/categories/,Categories
> > > https://localhost:4443/employees/2/#this,https://localhost:4443/categories/1/,Beverages
> > > https://localhost:4443/employees/2/#this,https://localhost:4443/categories/1/#this,Beverages
> > > https://localhost:4443/employees/2/#this,https://localhost:4443/categories/2/,Condiments
> > > https://localhost:4443/employees/2/#this,https://localhost:4443/categories/2/#this,Condiments
> > > https://localhost:4443/employees/2/#this,https://localhost:4443/categories/3/,Confections
> > > https://localhost:4443/employees/2/#this,https://localhost:4443/categories/3/#this,Confections
> > > https://localhost:4443/employees/2/#this,https://localhost:4443/categories/4/,Dairy
> > > Products
> > > https://localhost:4443/employees/2/#this,https://localhost:4443/categories/4/#this,Dairy
> > > Products
> > > https://localhost:4443/employees/2/#this,https://localhost:4443/categories/5/,Grains/Cereals
> > > ....
> > >
> > > Dydra's result is the one I'm going after, and is based on my
> > > understanding of OPTIONAL. But is it actually correct?
> > >
> > > And if Dydra is correct, what is Fuseki doing here? I would have
> > > expected the ?reportsToEmployee bindings from the appended OPTIONAL to
> > > be joined against the first result (without OPTIONAL), but that is not
> > > the case?
> > >
> > > Thanks.
> > >
> > > Martynas
